Article Type:
Research Article

A Simple Seasonal Forecast Update of Tropical Cyclone Activity

Johnny C. L. Chan Laboratory for Atmospheric Research, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China

Search for other papers by Johnny C. L. Chan in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Oct 2008
DOI:
https://doi.org/10.1175/2008WAF2007061.1
Page(s):
1016–1021
Restricted access

Abstract

A simple method based on the cumulative number of tropical cyclones (TCs) up to a given month in the early season is proposed to update the seasonal prediction of the annual number of TCs in a given ocean basin. For the western North Pacific, if this number is below normal by July or August, it is very likely that the annual activity will also be below normal. The reverse (for relating above-normal number with above-normal annual activity) is also true although the probability is smaller than for the below-normal category. Similar results are found for TCs in the eastern North Pacific and the North Atlantic, with the latter having the smallest likelihood. These results change only slightly when the samples are separated into dependent and independent subsets.

Corresponding author address: Johnny Chan, Dept. of Physics and Materials Science, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong, China. Email: johnny.chan@cityu.edu.hk

Abstract

A simple method based on the cumulative number of tropical cyclones (TCs) up to a given month in the early season is proposed to update the seasonal prediction of the annual number of TCs in a given ocean basin. For the western North Pacific, if this number is below normal by July or August, it is very likely that the annual activity will also be below normal. The reverse (for relating above-normal number with above-normal annual activity) is also true although the probability is smaller than for the below-normal category. Similar results are found for TCs in the eastern North Pacific and the North Atlantic, with the latter having the smallest likelihood. These results change only slightly when the samples are separated into dependent and independent subsets.

Corresponding author address: Johnny Chan, Dept. of Physics and Materials Science, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong, China. Email: johnny.chan@cityu.edu.hk

Save
Cover Weather and Forecasting
Weather and Forecasting

  • Camargo, S. J., Barnston A. G. , Klotzbach P. J. , and Landsea C. W. , 2007: Seasonal tropical cyclone forecasts. WMO Bull., 56 , 297–309.

    • Search Google Scholar
    • Export Citation

  • Chan, J. C. L., Shi J. E. , and Lam C. M. , 2001: Improvements in the seasonal forecasting of tropical cyclone activity over the western North Pacific. Wea. Forecasting, 16 , 997–1004.

    • Search Google Scholar
    • Export Citation

  • Gray, W. M., 1968: Global view of the origin of tropical disturbances and storms. Mon. Wea. Rev., 96 , 669–700.

  • Gray, W. M., 1984: Atlantic seasonal hurricane frequency. Part I: El Niño and 30 mb Quasi-Biennial Oscillation influences. Mon. Wea. Rev., 112 , 1649–1668.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Gray, W. M., Landsea C. W. , Mielke P. W. Jr., and Berry K. J. , 1993: Predicting Atlantic Basin seasonal tropical cyclone activity by 1 August. Wea. Forecasting, 8 , 73–86.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Klotzbach, P. J., 2007: Recent developments in statistical prediction of seasonal Atlantic basin tropical cyclone activity. Tellus, 59A , 511–518.

    • Search Google Scholar
    • Export Citation

  • Saunders, M. A., and Lea A. S. , 2005: Seasonal prediction of hurricane activity reaching the coast of the United States. Nature, 434 , 1005–1008.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 170 57 4
PDF Downloads 69 23 2